oil pressure issue....

qtstorm95

Registered User
Hey guys- have a quick question for yall:) ...had that brand new long block put in the sbird but it has a small oil pressure issue now:mad: . the issue is this-once it warms up it wont hold oil pressure when its in gear(drive or reverse)if im stopped with my foot on the brake.the oil pressure gauge will drop enough to get the check gauges lite to come on the dash. now when its in park n neutral its fine. its real easy to keep the pressure up if i just 'rest' my foot on the gas when its in gear(round 800rpm's),with my foot on the brake too. im not into playing games with the super coupe when it comes to easy drivability. the shop that installed the engine said it needs a high flow oil pump-dont think so cause it didnt have one b4.:confused: i did take it back to the shop and he said the pressure never went below 10-11 psi(after the new oil pressure gauge sending unit was put in)...i dont think they checked it correctly cause the pressure just drops fast. she only has a few upgrades so none of those should do it now.any of u guys ever get this issue after an upgrade....ie underdrive pulleys? other than this it runs GREAT!:D if any of you are willing-can u check this out? thanks for reading this huge post!
-qtstorm95
 
You need 10psi of oil pressure for every 1000rpms. If its idling then you need 10 psi, 2000rpm 20psi, 3000rpm 30psi...Etc.. So my question is this?? Whats the rest of the oil pressure readings?? Not just at idle. Who built the shortblock?? What were the main and rod bearing oil clearances?? If they are probably a little loose, which isnt necessarily a bad thing. You want a performance engine setup a little loose (.0025 - .003). Im thinking that the shop is correct is stating you could use a HPOP. For a hundred bucks its definetly worth it. Ive got one on my new engine.....Its also external, so the engine doesnt need to be removed?? I think you know what you need to do. Also, stock sending units arnt ever accurate, even worse below about 12-15psi....Dave
 
thanks Dave 4 the reply! the engine is a brand new longblock from supercoupeperformance.com so all the clearances should be fine there. everything is the same as b4 the engine swap except the 5% super pulley and adjustable fuel pressure regulator n steel tensioner pulleys. all the other upgrades were just transfered to the new longblock(3pc underdrive pulleys...no real major upgrades are on the car). everything ran fine b4...the head gaskets just gave out is y it was swapped. dont understand y a new longblock with a new oil pump isnt working correct.....
 
Todd has a very good point. I did not ask the question since every 3.8l/4.2l i have ever replaced has come with a new timing cover installed for this reason. Ford always included one. Never seen one not come with it. I didnt realize this was an SCP engine. You need to get hot and cold oil pressure readings and call them and let them make a call. Its their engine and warranty. See what they have to say...
 
Are you using the factory gauge, or an aftermarket one? If I remember correct, these factory oil pressure gauges are really more like glorified idiot lights. The sending unit/gauge just tells you the presence of pressure, not how much. That's why the needle doesn't move up or down with changes in engine speed. I saw a mod on TCCoA about installing a different sending unit & soldering in a resister on the gauge cluster so that the needle actually responds to changes in pressure. Anyway, you might have a bad sending unit or gauge, or an electrical connection problem in between.
 
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can you tell me where the oil pressure switch is located on the 3.8SC?

It's located in the front of the engine on the side of the timing cover on the drivers side about even with the water pump. If your car still has the black support bracket for the power steering pump that runs from the water pump to the box the switch is kind of hidden behind it.
 
Same Issue! Oil Pressure drops after temperature is reached.

I hate to Hijack this thread but I have the Exact same issue as the OP here. Only difference is it's the original engine. What was the outcome on this or anyone have any input? Thanks
 
I hate to Hijack this thread but I have the Exact same issue as the OP here. Only difference is it's the original engine. What was the outcome on this or anyone have any input? Thanks

Just remember that the stock oil pressure gauge isn't accurate at all, it really just lets you know if you have oil pressure or not. Basically it's just an idiot light with a needle which doesn't mean squat. You need to install an aftermarket unit to be able to see actual oil psi pressure.
 
most of the time you just need to replace the sending unit behind the PS bracket. The sending unit is basically just a switch. When it sees 7psi or so the gauge goes to about 3/4 and should never move.
 
most of the time you just need to replace the sending unit behind the PS bracket. The sending unit is basically just a switch. When it sees 7psi or so the gauge goes to about 3/4 and should never move.

Alright, so I already replaced it several months back. Orielly gave me two, said one was for the gauge and one for the light I believe. Is this true? Again, same issue as above. Starts fine and idles fine. Once she gets warmed up the gauge starts to bottom out while in a low idle drive or reverse (Mainly Reverse) and then the "Check Gauges" light lights up and it will stall or almost stall.
 
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Invest in a oil pressure gauge. Doesn't have to be a high dollar unit as the $25 part store special will work for a base line. Other than that check your wires.
 
You could do the pressure gage mod to the gage cluster(jumpering out the resistor on the back of the cluster, then install an actual pressure sending unit. You may have to make an adapter to reposition the sender to get it to fit. For now I would just go get a manual gage kit and install it, until you can get it sorted out. Most fords are this way. My '99 F250 v10 is set up the same way.
MikeH
 
What's with the engine almost stalling then? Is that a normal condition when this occurs? Thought I read somewhere that the computer will limit the performance of the engine when this occurs but might be wrong.
 
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